1. Field of the Invention
The present invention relates to an apparatus and method for adjusting the output level of audio data to be reproduced in a digital audio system.
2. Background of the Related Art
FIG. 1 is a block diagram showing the configuration of a related art digital audio system. Various digital audio systems, for example, a portable terminal such as an MP3 player, a portable computer, and a personal computer, each include an audio source 10, an audio codec 11, an audio controller 12 and an audio amplifier 13.
The audio source 10 is a recording medium for recording/storing audio files of various types such as an MP3 audio type, MPEG2 audio type and AC3 audio type, which may be, for example, an optical disc, hard disc or memory. The audio codec 11 decodes an audio file read from the audio source 10 into the original audio data to be reproduced and outputs the decoded audio data to the audio amplifier 13, or encodes external input audio data into an audio file so that the encoded audio file can be recorded in the audio source 10.
The audio controller 12 is adapted to control the encoding and decoding operations of the audio codec 11, and adjust the gain of the audio amplifier 13 based on an audio volume level set by a user. The audio amplifier 13 acts to amplify the audio data to be reproduced, outputted from the audio codec 11, at the adjusted gain and output the amplified audio data to a speaker.
Thus, the user of the related art digital audio system, configured and operated as described above, can download and store desired audio files of various types into the audio source 10, or encode external input audio data into an audio file of a predetermined specific format and record the encoded audio file in the audio source 10. Also, the user can play a desired one of the various types of audio files stored in the audio source 10, and listen to the played audio file at a desired audio output level by adjusting an audio volume key.
However, as described above, the related art digital audio system has various disadvantages. For example, the various types of audio files stored in the audio source 10 may not be uniform in their output levels because of their audio recording levels and recording formats set in their creation or recording processes. For at least this reason, the audio amplifier 13 may output audio data to be reproduced to the speaker at different output levels. In an example shown in FIG. 2, the user may sequentially play an MP3 audio file, MPEG2 audio file and AC3 audio file stored in the audio source 10 under the condition of adjusting the audio volume level to a value appropriate to the MP3 audio file. In this case, the output levels of the MPEG2 audio file and AC3 audio file played successively subsequently to the MP3 audio file may be different from that of the MP3 audio file because of their respective audio recording levels and recording formats set in the creation or recording processes. Accordingly, there occurs user inconvenience in having to adjust the audio volume level again.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.